/Engine/Plugins/Animation/ControlRig/Source/ControlRig/Public/Rigs/RigHierarchy.h
typedef TMulticastDelegate_TwoParams< void, const [FRigElementKey](API\Plugins\ControlRig\Rigs\FRigElementKey) &, const [FName](API\Runtime\Core\UObject\FName) & > FRigHierarchyMetadataChangedDelegate